Message type: E = Error
Message class:  COM_PRODUCT_TAX - Messages for Product Taxes 
Message number: 028
Message text: No assignment for country &1 (region &2)/tax type &3/tax group &4
You tried to convert tax data from the CRM System (tax type, tax group,
country, and possibly region) to tax data for an SAP System (tax
classification and country). However, the assignment rules required for
automatically transferring tax data have not been maintained.
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
To define the assignment rules required from here, choose
<LS>Customizing</> in the <LS>Performance Assistant</> toolbar.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message COM_PRODUCT_TAX028 indicates that there is no assignment for a specific country, region, tax type, and tax group in the system. This error typically arises when the system is unable to find the necessary tax configuration for a product or transaction based on the provided parameters.
Cause: Missing Tax Configuration: The primary cause of this error is that the tax configuration for the specified country, region, tax type, and tax group has not been set up in the system. Incorrect Data Entry: There may be a mistake in the data entry for the country, region, tax type, or tax group, leading to a mismatch. Changes in Tax Regulations: Changes in tax regulations or business requirements may not have been reflected in the system. Master Data Issues: The master data for the product or customer/vendor may not be correctly maintained, leading to the error.
Solution: Check Tax Configuration: Go to the transaction code OB40 (for tax
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
COM_PRODUCT_TAX023 There is no tax tariff code for country &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
COM_PRODUCT_TAX022 Enter a valid tax tariff code for country &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
COM_PRODUCT_TAX029 Assignment of tax data for product &1 in country &2 not unique
What causes this issue?  The tax data for product &V1& in country &V2& cannot be uniquely assigned to a tax data record in the connect...
COM_PRODUCT_TAX033 Note 454249 for table &2 country &1
What causes this issue?  There are duplicate entries for country &V1& in the table &V2&.System Response  The system issues an error me...
Click on this link to search all SAP messages.